Connective Tissue Flashcards
What does connective tissue provide? What does it carry? What does it mediate? What is it derived from?
provides: structural support and metabolic support for other tissues and organs
carries: blood vessels, function in tissue repair
mediates: exchange of nutrients/metabolites/waste products between tissue and circulation
derived: mesodermal mesenchyme
What is mesenchyme?
contains stellate to spinde-shaped cells, jelly-like extracellular matrix, and occasional fibers
What does mature connective tissue contain?
cells and extracellular material secreted by cells
What are the cells of connective tissue?
fibroblasts, reticular cells, and adipocytes
What are fibroblasts? What do they synthesize? What are myofibroblasts?
pointed, elongate, spindle-shaped cells
synthesize and maintain proteinaceous ground substance and connective tissue fibers
fibroblasts with contractile ability called myofibroblasts
they are mature cells
What are reticular cells? What do they synthesize?
of lymph nodes and bone marrow
look like branched fibroblasts
synthesize reticular fibers (made of reticulin) may have phagocytic function
ONLY need reticular cells when you need to sythesize lots of reticular fibers
What are adipocytes?
responsible for storage and metabolism of lipids
generally large, balloon-shaped clear spaces filled with lipids
What is ground substance? What is embedded in it?
extracellular organic matrix
various fibers embedded within matrix (collagen, reticulin, and elastin)
ex: scar tissue is mostly collagen
Type 1 collagen fiber facts
90% of collagen in body
loose and dense connective tissue of skin, tendons, ligaments, bone and fibrocartilage
What is type 2 collagen?
hyaline cartilage (less bubbles) and elastic cartilage (more bubbles)
What is type 3 collagen?
reticulin fibers, thin, branching, net-like fibers that stain black.
form structural support in organs
produced by reticular cells in lymph nodes and bone marrow and fibroblasts
What does argyrophilic mean? Example of it.
stains black with silver stain
type 3 collagen
What is type 4 collagen?
found in basement membrane, doesnt form fibers
What is type 5 collagen?
cornea, placenta, demo-epidermal junctions
What is collagenopathy? What is an example of it?
something is wrong with collagen
Ehlers-Danlos snydrome = affects type 5 collagen. Characterized by hyperextension of joints, skin fragility, and poor wound healing
How is collagen synthesized?
synthesized as pro collagen, composed of 3 alpha-polypeptide chains form triple helix
packed into secretory vesicles and secreted into ECS
then extracellular enzymatic modification to form tropocollagen monomers
polymerization of tropocollagen into larger bundles results in final formation of collagen microfibrils
What is collagen?
glycoproteinsl precursor protein produced by fibroblasts
What are elastic fibers? What are they synthesized by?
highly branched; random coiling pattern allows stretching, arranged in fibers and sheets, refractive
fibroblasts as tropoelastin precursor; polymerizes in ECM to form elastin
What are the two components of elastic fibers?
elastin: protein core similar to collagen
fibrillin: microfibrils that surround elastin
(stain black or blue)
What is Marfan’s syndrome?
autosomal dominant condition resulting in abnormal elastic fibers
characterized by tall stature, long limbs, and long, thin fingers
enlarged aorta
What are structural glycoproteins?
fibrillin and fibronectin
large polypeptides with branched polysaccharide side chains
What is fibronectin?
glycoprotein
found in basement membrane, aids in adhesion between cell membranes, and extracellular matrix, via interaction of adhesion molecules known as integrins
What is laminin?
sulfated glycoprotein; major component of basement membrane, produced by most epithelial and endothelial cells
What is enactin?
sulfated glycoproteinl binds with laminin
